With development of circuit switching, communications networks meet requirements of placing calls and performing digital program control by people, and are a protocol system that is complete from a physical layer to an application layer, and desirably supports coordination between networks and applications, for example, sensing of a fault at a bottom layer by an upper layer, and cooperation of upper-layer flow control and a network status.
As packet switching networks, especially, Internet Protocol (IP) networks emerge, a condition for internetworking and reusing of network resources is provided. With development of science and technologies, software-defined networking (SDN) derives based on an IP network. The SDN is a new network architecture, and a core technology of the SDN is separating a control plane from a data plane of a network device, thereby implementing flexible control of network traffic, and providing a desirable platform for innovation of core networks and applications.
In a data center network, data flows of different tenants need to be isolated by using different virtual local area networks (vVLAN). However, there are only 4094 conventional VLANs, which cannot meet isolation requirements of over 4K tenants. In this case, a virtual extensible local area network (VXLAN) technology is invented. The VXLAN technology enables multiple virtual machines (VM) in a same VXLAN to perform communication across three-layer networks, which can effectively break through a limitation of 4K tenants in a conventional VLAN. Therefore, the VXLAN technology is applied more widely.
In the prior art, when the VXLAN technology is used for communication in an SDN network architecture, an SDN controller delivers, after creating a VM, a MAC address forwarding table of the VM to a VXLAN gateway to which the VM belongs. There may be multiple VMs in a VXLAN gateway, and in this case, the VXLAN gateway needs to store a large number of MAC address forwarding tables, but a MAC address forwarding table of each VM is not needed all the time. Therefore, a disadvantage of relatively severe waste of resources exists in current VXLAN gateways.